The invention generally relates to the field of article gripping mechanisms such as those employed for gripping workpieces or tools for transport; interchanges; etc. In particular, the invention relates to the type of gripper which may be typically employed on a machine loader or on a robot machine utilizing a gripping apparatus as its end effector.
Article grippers of the actuated finger type have been developed wherein a gripping finger or, more commonly, a pair of opposed gripping fingers are pivotally carried on a housing and are biased to a clamped position by a mechanical device such as a compression spring. At selected times, pressurized fluid is utilized to overcome the mechanical biasing force to power the fingers to an unclamped position to extract or insert an article. In some instances, the biasing clamp spring is merely an assist to a primarily power-actuated clamp element, so that in the event of a power failure a "fail-safe" mechanism is accomplished, which will retain the clamp and not drop the article.
It has been appreciated by the inventor herein, that during transport of an article which is clamped by a biasing spring or similar-type force mechanisms, unusually large momentary acceleration forces may occur which actually overcome the clamping spring force, causing an article to be loosened from its clamped state. In such event, the article may be mispositioned for subsequent operations or may, in fact, be completely dropped, causing damage.
Applicant has obviated the difficulties inherent in the prior art devices by providing a latch for an article gripper tending to make the clamp fingers irreversibly movable under the influence of external forces until such selected time as an unclamp force is applied.
It is, therefore, an object of the present invention to provide a locking type finger gripping apparatus.
Another object of the present invention is to provide a lock for a finger gripping apparatus which may be easily applied in sequence with the clamping and unclamping actuating forces.